Objective: To investigate the expressions of YAP1, E-cadherin and N-cadherin in gastric cancer tissue and their significance. Methods: The expressions of YAP1, N-cadherin and E-cadherin proteins in tissue microarray containing 135 samples of gastric cancer tissue and adjacent tissue were determined by immunohistochemical staining. The relations of YAP1 expression with E-cadherin and N-cadherin expressions as well as with clinicopathologic characteristics and prognosis of the patients were analyzed. Results: In gastric cancer tissue compared with adjacent non-tumor tissue, the YAP1 expression was increased and E-cadherin expression was decreased significantly (both P<0.05), but the N-cadherin showed no significant difference (P>0.05). There was a negative correlation between YAP1 expression and E-cadherin expression (r=–0.273, P=0.032), and a positively correlation between YAP1 expression and N-cadherin (r=0.304, P=0.019) in gastric cancer tissue. The expression of YAP1 in gastric cancer was correlated with lymphatic metastasis and vascular invasion (P<0.05), and the overall survival rate in patients with YAP1 positive expression was significantly lower than that in those with YAP1 negative expression (χ2=4.354, P=0.037). Conclusion: The expressions of YPA1 and E-cadherin are significantly changed in gastric cancer tissue, and high YAP1 expression is closely related to the unfavorable clinicopathologic features and poor prognosis in the gastric cancer patients.